Topband: Sudden Ionospheric Disturbance

[N7DF]

>From spaceweather.com
 
IONOSPHERIC DISTURBANCE: Yesterday's M2-class solar flare bathed Earth's upper atmosphere in X-rays and caused a wave of ionization to sweep over Europe. This actually improved the propagation of low-frequency radio signals, which use the ionosphere as a reflector to skip over the horizon. A SID monitor operated by Rudolf Slosiar in Bojnice, Slovakia, recorded the surge in signal strength: 
 
SID" stands for Sudden Ionospheric Disturbance, and a "SID monitor" is a radio receiver that monitors ~20 kHz signals from distant transmitters. "My system clearly detected the effects of the solar flare," says Slosiar. "The decay of the signal shows that it took about 72 minutes for the ionosphere to recombine [and relax to its pre-flare state]."
With solar activity on the rise, sudden ionospheric disturbances will become more common. Interested?
 Stanford University tells you how to build your own SID monitor 
http://solar-center.stanford.edu/SID/sidmonitor/